Semiconductor device and method of making the same

摘要

1,016,343. Semi-conductor devices. HUGHES AIRCRAFT CO. Nov. 16, 1962 [Dec. 5, 1961], No. 43433/62. Heading H1K. A semi-conductor element is bonded to a layer of conductive material provided on an area of a ceramic body. Surface diffusion of an N-type dopant into a high resistivity germanium layer 12 (Fig. 3), epitaxially formed on a P + germanium crystal 11, produces a layer 13. The body is then sliced forming bars 10 which are subsequently etched to expose a region 14 of original crystal. A relief pattern of mesas is formed on a disc 15 (Fig. 4, not shown) of unfired alumina by, for example, ultrasonic drilling and the disc is subsequently fired to harden the material. Protruding structures 17, 18 and 21 which form collector base and emitter conductor supports respectively, and the disc perimeter surface 34 (Fig. 8, not shown) are plated with a molybdenum-manganese coating followed by layers of copper and nickel by electrolytic or electroless plating methods. Electrolytic plating of lead-antimony 51 on to arms 18 of the base support and arm 21 of the emitter support followed by gallium or lead gallium 52 on emitter support 21 and on collector support 17 provides the necessary dopant materials. Tantalum leads 27, 28 and 29 are then bonded to their respective supports in a heating process which produces a nickel-copper bonding alloy on the molybdenum-manganese surface. In an alternative method the metallisation steps precede shaping of the disc. The bar 10 of Fig. 3 is then placed on the completed disc of Fig. 8 so that regions 13, 18 and 21 are in contact as are regions 14 and 17. After etching and cleaning steps the assembly is then heated to fuse the parts together and the PNP transistor so formed may be encapsulated in a metal or ceramic hermetically sealed housing (Figs. 10 and 11, not shown). In a variation of the production method, surface diffusion of antimony into a P-type germanium crystal produces an N-type surface region and with a back-strap ohmically bonded thereto a doubledoped alloy is alloyed to the N-type surface to produce a P-type emitter region with an underlying diffused base region.